• Title/Summary/Keyword: Laser absorption spectroscopy

Search Result 118, Processing Time 0.034 seconds

Laser absorption spectroscopy of ternary gas mixture of He-Ne-Xe in External Electrode Fluorescent Lamp (EEFL) (레이저 흡수 분광법을 이용한 He-Ne-Xe 상종가스의 외부전곡 램프의 $1s_4$ 공명준위와 $1s_5$ 준안정준위의 제논 원자 밀도에 대한 연구)

  • Jeong, S.H.;Oh, P.Y.;Lee, J.H.;Cho, G.S.;Choi, E.H.
    • Journal of the Korean Vacuum Society
    • /
    • v.15 no.6
    • /
    • pp.576-580
    • /
    • 2006
  • Mercury-free lamp, external electrode fluorescent lamp (EEFL) which includes the xenon gas, is now going on the research for the replacement of mercury lamp. The densities of excited xenon atom in the $1s_4$ resonance state and the $1s_5$ metastable state are investigated in the EEFL by a laser absorption spectroscopy under various gas pressures. We have measured the absorption signals for both $1s_4$ resonance and the $1s_5$ metastable state in the EEFL by varying the discharge currents for a given pressure. This basic absorption characteristic is very important for improvement of the VUV luminous efficiency of the EEFL as well as plasma display panel.

Analysis of Xe Plasma by LAS (레이저 흡수법을 이용한 제논 플라즈마 분석)

  • Yang, Jong-Kyung;Her, In-Sung;Lee, Jong-Chan;Choi, Yong-Sung;Park, Dae-Hee
    • Proceedings of the KIEE Conference
    • /
    • 2005.11a
    • /
    • pp.220-222
    • /
    • 2005
  • We can classify two cases in a way to observe an atom of gas state or a molecule using the laser. First case is way to use dispersion phenomenon like Rayleigh scattering, Thomson scattering, Mie scattering, Raman Scattering. And Second case is a way to use change phenomenon like a LAS (Laser Absorption Spectroscopy), LIF (Laser Induced Fluorescent). In this paper, we have measured the meta-stable density and the distribution by using a LAS method in Xe discharge lamp. The laser absorption spectroscopy (LAS) is useful to investigate the behavior of such species. The xenon atoms in the $1S_4$ and $1S_5$ generate excited $Xe^*$(147nm) and $Xe_{2}^*$(173nm) dimers in Xe plasma. It is found that the intensity of VUV 147nm emission is proportional to that of the IR 828nm emission, and the VUV 173nm emission is roughly proportional to that of the IR 823nm emission. The laser is used CW laser that consist of AlGaAs semiconductor and energy level is used 823.16nm wavelength. We measured signal of monochrometer from the lamp center while will change a discharge electric current by 6mA in 3mA and calculated meta-stable state density of a xenon atom through a measured value.

  • PDF

Temperature measurement of the spray flame using micro scale absorption bands and line strength (마이크로 스케일의 흡수선과 흡수강도를 이용한 분무화염의 온도측정)

  • Choi, G.M.
    • Journal of ILASS-Korea
    • /
    • v.7 no.2
    • /
    • pp.1-6
    • /
    • 2002
  • It is necessary to develope a high frequency diode laser sensor system based on the absorption spectroscopy for the measurement of temperature of the spray flame. DFB diode laser operating near $2.0{\mu}m$ was used to scan over selected $H_2O$ transitions near $1.9{\mu}m\;and\;2.2{\mu}m$, respectively. The measurement sensitivity at wide range of sweep frequency was evaluated using multi-pass cell containing $CO_2$ gas. This diode laser absorption sensor with high temporal resolution up to 10kHz was applied to measure the gas temperature in the spray flame region of liquid-gas 2-phase counter flow flame. The successful demonstration of time series temperature measurement in the spray flame gives us motivation of trying to establish non-intrusive temperature measurement method in the practical spray flame.

  • PDF

Development of AI oxygen temperature measurement technology using hyperspectral optical visualization technology (초분광 광학가시화 기술을 활용한 인공지능 산소온도 측정기술 개발)

  • Jeong Hun Lee;Bo Ra Kim;Seung Hun Lee;Joon Sik Kim;Min Yoon;Gyeong Rae Cho
    • Journal of the Korean Society of Visualization
    • /
    • v.21 no.1
    • /
    • pp.103-109
    • /
    • 2023
  • This research developed a measurement technique that can measure the oxygen temperature inside a high temperature furnace. Instead of measuring only changes in frequency components within a small range used in the existing variable laser absorption spectroscopy, laser spectroscopy technology was used to spread out wavelength of the light source passing through the gas Based on a total of 20,000 image data, research was conducted to predict the temperature of a high-temperature furnace using CNN with black and white images in the form of spectral bands by temperature of 25 to 800 degrees. The optimal model was found through Hyper parameter optimization, R2 score is 0.89, and the accuracy of the test data is 88.73%. Based on this research, it is expected that concentration measurement and air-fuel ratio control technology can be applied.

Hydroxyl Radical Measurements in the Flame Using LIF (레이저유도 형광법을 이용한 화염내 OH 농도분포 계측)

  • Lee, Byeong-Jun;Gil, Yong-Seok;Jeong, Seok-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.20 no.2
    • /
    • pp.710-719
    • /
    • 1996
  • Laser applied combustion diagnostic techniques-laser induced fluorescence (LIF) and coherent anti-Stokes Ramann spectroscopy (CARS)-are demonstrated. The profiles of hydroxyl radical (OH) and temperature in the counterflow burner are measured and compared with the numerical results. OH radical is excited on the Q$_1$(6) line of the $A^2$$\sum^+$$\leftarrow$$X^2{\prod}$(1, 0) band transition (281.1 nm) and LIF signal is measured at the the bands of (0, 0) and (1, 1) transition (306~326 nm). Absolute OH radical is obtained by using the laser absorption technique. The quenching effects are considered. Temperature is measured using broadband CARS system. Two dimensional OH radical profile is also obtained. The profiles of OH radical and temperature are found to agree well with those of numerical calculation.

Study on a cavity ring-down spectrometer with continuous wave laser sources (연속발진 레이저를 이용한 공동 광자감쇠 분광기 연구)

  • 유용심;한재원;김재완;이재용;이해웅
    • Korean Journal of Optics and Photonics
    • /
    • v.9 no.4
    • /
    • pp.240-244
    • /
    • 1998
  • Cavity ring-down spectroscopy (CRDS) is a high-sensitive laser spectroscopic technique capable of measuring concentrations of trace gases. We have demonstrated a new design of the CRDS spectrometer with a continuous wave (CW) laser. The ring-dwon signal is produced through blocking the incident CW laser by scanning the cavity length fast toward off-resonance iwth PZT (piezoelectric transducer). We have also measured an absorption spectrum of acetylene overtone transitions near 570 nm at the pressure of 2700 Pa, and the minimum detectable absorption coefficient has been found to be about $3{\times}10^{-9}\cm^{-1}$.

  • PDF

The Quantitative Characterization of the Dispersion State of Single-Walled Carbon Nanotubes (단일벽 탄소나노튜브의 분산도 정량적 평가)

  • Yoon, Do-Kyung;Choi, Jae-Boong;Kim, Young-Jin;Baik, Seung-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.31 no.4
    • /
    • pp.483-489
    • /
    • 2007
  • We have investigated quantitative measurement techniques of the degree of dispersion of single-walled carbon nanotubes (SWNTs). SWNTs were suspended in aqueous media using a sodium dodecyl sulfate (SDS) surfactant. SWNTs with different dispersion states were prepared by controlling the intensity and time of sonication and centrifugation. The laser spectroscopic techniques were employed to characterize the dispersion state; i.e., raman fluorescence and absorption spectroscopic techniques. Raman spectroscopy has been used to probe the dispersion and aggregation state of SWNTs in solution. Individually suspended SWNTs show increased fluorescence peaks and decreased roping peaks at a raman shift 267 $cm^{-1}$ compared with the samples containing bundles of SWNTs. The ultraviolet-visible-near infrared (UV-vis-NIR) absorption spectrum of decanted supernatant samples show sharp van Hove singularity peaks

Analysis of Acetone Absorption Spectra Using Off-axis Integrated Cavity Output Spectroscopy for a Real-time Breath Test

  • Lim Lee;Yonghee Kim;Byung Jae Chun;Taek-Soo Kim;Seung-Kyu Park;Kwang-Hoon Ko;Ki-Hee Song;Hyunmin Park
    • Current Optics and Photonics
    • /
    • v.7 no.6
    • /
    • pp.761-765
    • /
    • 2023
  • We analyzed the absorption spectra of acetone in the 3.37 ㎛ mid-infrared range using the off-axis integrated cavity output spectroscopy technique to develop a real-time, in-line breath analysis device. The linear relationship between acetone concentration and absorption increase was confirmed as 0.32%/ppm, indicating that the developed device allows for a quantitative analysis of acetone concentration in exhaled breath. To further confirm the feasibility of using our device for breath analysis, we measured the acetone concentration of human breath samples at the sub-ppm level.

Spatiotemporal Behavior of the Excited Xe Atom Density in the $1s_5$ Metastable State According to the Hoof-type Electrode Structure in an Alternating-current Plasma Display Pane

  • Kim, Yong-Hee;Hong, Young-June;Choi, Joon-Ho;Cho, Byeong-Seong;Uhm, Han-Sub;Choi, Eun-Ha
    • Journal of Information Display
    • /
    • v.11 no.4
    • /
    • pp.149-153
    • /
    • 2010
  • To improve the luminescence characteristics of high-efficiency alternating-current plasma display panels (AC-PDPs), we developed a new hoof-type electrode structure, and we studied the spatiotemporal behavior of the density of the excited Xenon atom in the $1s_5$ metastable state via laser absorption spectroscopy. Using this structure, the maximum density of the excited Xenon atom per cell was improved by 2.4 times that when the conventional electrode structure was used.

Picosecond Absorption Kinetic Spectrometer with a Laser and a Streak Camera

  • Jang, Du-Jeon
    • Proceedings of the Optical Society of Korea Conference
    • /
    • 1990.02a
    • /
    • pp.172-176
    • /
    • 1990
  • A high resolution picosecond absorption kinetic spectrometer utilizing dye emission and a streak camera is presented and compared with other methods of picosecond transient absorption measurements. Typical transient absorption and bleach recovery kinetics measured with this spectrometer are shown. Single wavelength transient absorption or ground state bleach recovery kinetics are determined on the basis of a single laser shot, so that the samples are relatively free frm decomposition by irradiation. Excellent kinetics may be obtained from the near UV to the near IR and are not subject to interference from luminescence of samples. The sensitivity of this spectrometer is very high and it is reasonably easy and convenient to set up and use.

  • PDF